diff --git a/configure.ac b/configure.ac
index bbb655b0b..da6703ccb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -104,7 +104,10 @@ AC_CHECK_DECLS([__CYGWIN__])
 AC_SEARCH_LIBS(accept, network socket)
 
 # Checks for library functions.
-AC_CHECK_FUNCS([accept4 getaddrinfo gettimeofday inet_pton inet_ntop select socket strerror strlcpy])
+AC_CHECK_FUNCS([accept4 getaddrinfo gettimeofday inet_pton inet_ntop select socket strerror_r strlcpy])
+
+# Check which flavour of strerror_r is available on the target
+AC_FUNC_STRERROR_R
 
 # Required for MinGW with GCC v4.8.1 on Win7
 AC_DEFINE(WINVER, 0x0501, _)
diff --git a/docs/index.md b/docs/index.md
index 89fcbbba8..6e1909829 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -245,9 +245,11 @@ shall return either a NULL value (if returning a pointer) or a negative value
 (if returning an integer), and the actual error code shall be stored in the
 `errno` variable.
 
-The *modbus_strerror()* function is provided to translate libmodbus-specific
-error codes into error message strings; for details refer to
-[modbus_strerror](modbus_strerror.md).
+The *modbus_strerror_r()* function is provided to translate libmodbus-specific
+error codes into error message strings; for details refer to:
+
+- [modbus_strerror_r](modbus_strerror_r.md)
+- [modbus_strerror](modbus_strerror.md) **deprecated**
 
 ## Miscellaneous
 
diff --git a/docs/modbus_close.md b/docs/modbus_close.md
index 05cc080eb..02c905799 100644
--- a/docs/modbus_close.md
+++ b/docs/modbus_close.md
@@ -26,7 +26,9 @@ modbus_t *ctx;
 
 ctx = modbus_new_tcp("127.0.0.1", 502);
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno), buf, sizeof(buf));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_connect.md b/docs/modbus_connect.md
index 541d9d982..14ccf1a65 100644
--- a/docs/modbus_connect.md
+++ b/docs/modbus_connect.md
@@ -29,7 +29,9 @@ modbus_t *ctx;
 
 ctx = modbus_new_tcp("127.0.0.1", 502);
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno), buf, sizeof(buf));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_mapping_new.md b/docs/modbus_mapping_new.md
index bedac63fd..3091cbfa0 100644
--- a/docs/modbus_mapping_new.md
+++ b/docs/modbus_mapping_new.md
@@ -45,9 +45,10 @@ mb_mapping = modbus_mapping_new(
     INPUT_REGISTERS_ADDRESS + INPUT_REGISTERS_NB
 );
 if (mb_mapping == NULL) {
+    char buf[128];
     fprintf(
         stderr, "Failed to allocate the mapping: %s\n",
-        modbus_strerror(errno)
+        modbus_strerror_r(errno, buf, sizeof(buf))
     );
     modbus_free(ctx);
     return -1;
diff --git a/docs/modbus_mapping_new_start_address.md b/docs/modbus_mapping_new_start_address.md
index c72cd3d49..8cf5d8f91 100644
--- a/docs/modbus_mapping_new_start_address.md
+++ b/docs/modbus_mapping_new_start_address.md
@@ -70,9 +70,10 @@ mb_mapping = modbus_mapping_new_start_address(
     INPUT_REGISTERS_ADDRESS, INPUT_REGISTERS_NB
 );
 if (mb_mapping == NULL) {
+    char buf[128];
     fprintf(
         stderr, "Failed to allocate the mapping: %s\n",
-        modbus_strerror(errno)
+        modbus_strerror_r(errno, buf, sizeof(buf))
     );
     modbus_free(ctx);
     return -1;
diff --git a/docs/modbus_new_rtu.md b/docs/modbus_new_rtu.md
index 15dac8e3b..e6375479b 100644
--- a/docs/modbus_new_rtu.md
+++ b/docs/modbus_new_rtu.md
@@ -86,7 +86,9 @@ if (ctx == NULL) {
 }
 
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_new_tcp.md b/docs/modbus_new_tcp.md
index 1bb2ae944..74b72eb99 100644
--- a/docs/modbus_new_tcp.md
+++ b/docs/modbus_new_tcp.md
@@ -48,7 +48,9 @@ if (ctx == NULL) {
 }
 
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_new_tcp_pi.md b/docs/modbus_new_tcp_pi.md
index fa0b5c0ca..b0e9282bc 100644
--- a/docs/modbus_new_tcp_pi.md
+++ b/docs/modbus_new_tcp_pi.md
@@ -49,7 +49,9 @@ if (ctx == NULL) {
 }
 
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_read_registers.md b/docs/modbus_read_registers.md
index 8f853cc7c..28cdcc5a5 100644
--- a/docs/modbus_read_registers.md
+++ b/docs/modbus_read_registers.md
@@ -40,14 +40,17 @@ int i;
 
 ctx = modbus_new_tcp("127.0.0.1", 1502);
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
 
 rc = modbus_read_registers(ctx, 0, 10, tab_reg);
 if (rc == -1) {
-    fprintf(stderr, "%s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "%s\n", modbus_strerror_r(errno, buf, sizeof(buf));
     return -1;
 }
 
diff --git a/docs/modbus_rtu_set_rts.md b/docs/modbus_rtu_set_rts.md
index 5a33d1c6a..0d867af0e 100644
--- a/docs/modbus_rtu_set_rts.md
+++ b/docs/modbus_rtu_set_rts.md
@@ -49,14 +49,17 @@ modbus_rtu_set_serial_mode(ctx, MODBUS_RTU_RS485);
 modbus_rtu_set_rts(ctx, MODBUS_RTU_RTS_UP);
 
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
 
 rc = modbus_read_registers(ctx, 0, 7, tab_reg);
 if (rc == -1) {
-    fprintf(stderr, "%s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "%s\n", modbus_strerror_r(errno, buf, sizeof(buf)));
     return -1;
 }
 
diff --git a/docs/modbus_send_raw_request.md b/docs/modbus_send_raw_request.md
index 66ceceaa2..975f3b420 100644
--- a/docs/modbus_send_raw_request.md
+++ b/docs/modbus_send_raw_request.md
@@ -40,7 +40,9 @@ uint8_t rsp[MODBUS_TCP_MAX_ADU_LENGTH];
 
 ctx = modbus_new_tcp("127.0.0.1", 1502);
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_set_slave.md b/docs/modbus_set_slave.md
index efdeea386..bfcf9e3f0 100644
--- a/docs/modbus_set_slave.md
+++ b/docs/modbus_set_slave.md
@@ -66,7 +66,9 @@ if (rc == -1) {
 }
 
 if (modbus_connect(ctx) == -1) {
-    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    char buf[128];
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
     modbus_free(ctx);
     return -1;
 }
diff --git a/docs/modbus_strerror.md b/docs/modbus_strerror.md
index 9db8b799e..42ab34cc3 100644
--- a/docs/modbus_strerror.md
+++ b/docs/modbus_strerror.md
@@ -10,6 +10,9 @@ modbus_strerror - return the error message
 const char *modbus_strerror(int errnum);
 ```
 
+Warning, this function is *deprecated* since libmodbus **tbd** and has been
+replaced by *modbus_strerror_r()*.
+
 ## Description
 
 The *modbus_strerror()* function shall return a pointer to an error message
diff --git a/docs/modbus_strerror_r.md b/docs/modbus_strerror_r.md
new file mode 100644
index 000000000..ae10f5bf7
--- /dev/null
+++ b/docs/modbus_strerror_r.md
@@ -0,0 +1,50 @@
+# modbus_strerror_r
+
+## Name
+
+modbus_strerror_r - return the error message
+
+## Synopsis
+
+```c
+const char *modbus_strerro_r(int errnum, char buf[.buflen], size_t buflen);
+```
+
+## Description
+
+The *modbus_strerror_r()* function is a reentrant replacement for
+*modbus_strerror()*.
+
+The *modbus_strerror_r()* function returns a pointer to a string containing
+the error message. This may either be a pointer to a string that the
+function stores in *buf*, or a pointer to some (immutable) static string
+(in which case *buf* is unused). If the function stores a string in *buf*,
+then at most *buflen* bytes are stored. The string may be truncated if
+*buflen* is tool small and errnum is unknown. The string always includes a
+terminating null byte ('\0').
+
+As libmodbus defines additional error numbers over and above those defined
+by the operating system, applications should use *modbus_strerror_r()* in
+preference to the standard *strerror_r()* function.
+
+## Return value
+
+The *modbus_strerror()* function shall return a pointer to an error message
+string.
+
+## Errors
+
+No errors are defined.
+
+## Example
+
+Display an error message when a Modbus connection cannot be established
+
+```c
+if (modbus_connect(ctx) == -1) {
+    char buf[128]
+    fprintf(stderr, "Connection failed: %s\n",
+        modbus_strerror_r(errno, buf, sizeof(buf)));
+    abort();
+}
+```
diff --git a/src/modbus-rtu.c b/src/modbus-rtu.c
index b7749230c..99137c256 100644
--- a/src/modbus-rtu.c
+++ b/src/modbus-rtu.c
@@ -12,6 +12,7 @@
 #ifndef _MSC_VER
 #include <unistd.h>
 #endif
+#include "modbus.h"
 #include "modbus-private.h"
 #include <assert.h>
 
@@ -649,10 +650,11 @@ static int _modbus_rtu_connect(modbus_t *ctx)
     ctx->s = open(ctx_rtu->device, flags);
     if (ctx->s < 0) {
         if (ctx->debug) {
+            char buf[128];
             fprintf(stderr,
                     "ERROR Can't open the device %s (%s)\n",
                     ctx_rtu->device,
-                    strerror(errno));
+                    modbus_strerror_r(errno, buf, sizeof(buf)));
         }
         return -1;
     }
diff --git a/src/modbus.c b/src/modbus.c
index 0360d5ccd..622650e37 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -41,7 +41,9 @@ typedef enum {
     _STEP_DATA
 } _step_t;
 
-const char *modbus_strerror(int errnum)
+// returns NULL if the error belongs to the operating system, otherwise a
+// pointer to the error message.
+static const char *libmodbus_specific_error_text(int errnum)
 {
     switch (errnum) {
     case EMBXILFUN:
@@ -75,14 +77,82 @@ const char *modbus_strerror(int errnum)
     case EMBBADSLAVE:
         return "Response not from requested slave";
     default:
-        return strerror(errnum);
+        return NULL;
     }
 }
 
+const char *modbus_strerror(int errnum)
+{
+    const char *s = libmodbus_specific_error_text(errnum);
+
+    if (s) {
+        return s;
+    }
+    return strerror(errnum);
+}
+
+const char *modbus_strerror_r(int errnum, char *buf, size_t buflen)
+{
+    const char *s = libmodbus_specific_error_text(errnum);
+
+    if (s) {
+        return s;
+    }
+
+#if HAVE_STRERROR_R
+ /*
+  * The glibc provides 2 different versions of strerror_r.
+  *
+  * XSI-compliant version:
+  *     int strerror_r(int errnum, char *buf, size_t buflen);
+  *
+  * GNU-specific version:
+  *     char *strerror_r(int errnum, char *buf, size_t buflen);
+  *
+  * See "man 3 strerror_r" for details.
+  */
+#if STRERROR_R_CHAR_P
+    /* GNU-specific strerror_r() */
+    /*
+     * The statement below will hopefully result in a compiler warning if
+     * the XSI-compliant implementation is provided instead of the GNU-specific
+     * version (although detected by configure).
+     */
+    return strerror_r(errnum, buf, buflen);
+#else
+    /* XSI-complaint strerror_r() */
+    /*
+     * Neither POSIX nor the Linux man page specify the buffer content when
+     * strerror_r() completes unsuccessfully. Therefore, we initialize the
+     * buffer with '\0' before we call strerror_r(), and manually terminate
+     * the string in case strerror_r() signals an error.
+     */
+    memset(buf, 0, buflen);
+
+    /*
+     * The statement below will hopefully result in a compiler warning if
+     * the GNU-specific version is provided instead of the XSI-compliant
+     * implementation.
+     */
+    int res = strerror_r(errnum, buf, buflen);
+    if (res != 0)
+        buf[buflen - 1] = 0;
+
+    return buf;
+
+#endif /* STRERROR_R_CHAR_P */
+#else
+    /* fallback in case strerror_r() is not available */
+    snprintf(buf, buflen, "error %d", errnum);
+    return buf;
+#endif /* HAVE_STRERROR_R */
+}
+
 void _error_print(modbus_t *ctx, const char *context)
 {
     if (ctx->debug) {
-        fprintf(stderr, "ERROR %s", modbus_strerror(errno));
+        char buf[128];
+        fprintf(stderr, "ERROR %s", modbus_strerror_r(errno, buf, sizeof(buf)));
         if (context != NULL) {
             fprintf(stderr, ": %s\n", context);
         } else {
diff --git a/src/modbus.h b/src/modbus.h
index 55ef08a0d..07abbeeba 100644
--- a/src/modbus.h
+++ b/src/modbus.h
@@ -216,6 +216,7 @@ MODBUS_API int modbus_flush(modbus_t *ctx);
 MODBUS_API int modbus_set_debug(modbus_t *ctx, int flag);
 
 MODBUS_API const char *modbus_strerror(int errnum);
+MODBUS_API const char *modbus_strerror_r(int errnum, char *buf, size_t buflen);
 
 MODBUS_API int modbus_read_bits(modbus_t *ctx, int addr, int nb, uint8_t *dest);
 MODBUS_API int modbus_read_input_bits(modbus_t *ctx, int addr, int nb, uint8_t *dest);
diff --git a/tests/bandwidth-client.c b/tests/bandwidth-client.c
index 842462b59..394c348e0 100644
--- a/tests/bandwidth-client.c
+++ b/tests/bandwidth-client.c
@@ -76,7 +76,9 @@ int main(int argc, char *argv[])
         modbus_set_slave(ctx, 1);
     }
     if (modbus_connect(ctx) == -1) {
-        fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+        char buf[128];
+        fprintf(stderr, "Connection failed: %s\n",
+            modbus_strerror_r(errno, buf, sizeof(buf)));
         modbus_free(ctx);
         return -1;
     }
@@ -96,7 +98,9 @@ int main(int argc, char *argv[])
     for (i = 0; i < n_loop; i++) {
         rc = modbus_read_bits(ctx, 0, nb_points, tab_bit);
         if (rc == -1) {
-            fprintf(stderr, "%s\n", modbus_strerror(errno));
+            char buf[128];
+            fprintf(stderr, "%s\n",
+                modbus_strerror_r(errno, buf, sizeof(buf)));
             return -1;
         }
     }
@@ -133,7 +137,8 @@ int main(int argc, char *argv[])
     for (i = 0; i < n_loop; i++) {
         rc = modbus_read_registers(ctx, 0, nb_points, tab_reg);
         if (rc == -1) {
-            fprintf(stderr, "%s\n", modbus_strerror(errno));
+            char buf[128];
+            fprintf(stderr, "%s\n", modbus_strerror_r(errno, buf, sizeof(buf)));
             return -1;
         }
     }
@@ -171,7 +176,8 @@ int main(int argc, char *argv[])
         rc = modbus_write_and_read_registers(
             ctx, 0, nb_points, tab_reg, 0, nb_points, tab_reg);
         if (rc == -1) {
-            fprintf(stderr, "%s\n", modbus_strerror(errno));
+            char buf[128];
+            fprintf(stderr, "%s\n", modbus_strerror_r(errno, buf, sizeof(buf)));
             return -1;
         }
     }
diff --git a/tests/bandwidth-server-many-up.c b/tests/bandwidth-server-many-up.c
index f6eb7d7fb..da4bbc0cf 100644
--- a/tests/bandwidth-server-many-up.c
+++ b/tests/bandwidth-server-many-up.c
@@ -55,7 +55,9 @@ int main(void)
     mb_mapping =
         modbus_mapping_new(MODBUS_MAX_READ_BITS, 0, MODBUS_MAX_READ_REGISTERS, 0);
     if (mb_mapping == NULL) {
-        fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno));
+        char buf[128];
+        fprintf(stderr, "Failed to allocate the mapping: %s\n",
+            modbus_strerror_r(errno, buf, sizeof(buf)));
         modbus_free(ctx);
         return -1;
     }
diff --git a/tests/bandwidth-server-one.c b/tests/bandwidth-server-one.c
index c7ef1ab20..9edd4cedb 100644
--- a/tests/bandwidth-server-one.c
+++ b/tests/bandwidth-server-one.c
@@ -30,6 +30,7 @@ int main(int argc, char *argv[])
     modbus_mapping_t *mb_mapping = NULL;
     int rc;
     int use_backend;
+    char errbuf[128];
 
     /* TCP */
     if (argc > 1) {
@@ -61,7 +62,8 @@ int main(int argc, char *argv[])
     mb_mapping =
         modbus_mapping_new(MODBUS_MAX_READ_BITS, 0, MODBUS_MAX_READ_REGISTERS, 0);
     if (mb_mapping == NULL) {
-        fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno));
+        fprintf(stderr, "Failed to allocate the mapping: %s\n",
+            modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
         modbus_free(ctx);
         return -1;
     }
@@ -78,7 +80,8 @@ int main(int argc, char *argv[])
         }
     }
 
-    printf("Quit the loop: %s\n", modbus_strerror(errno));
+    printf("Quit the loop: %s\n",
+        modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
 
     modbus_mapping_free(mb_mapping);
     if (s != -1) {
diff --git a/tests/random-test-client.c b/tests/random-test-client.c
index c2ccf63fd..805a380c7 100644
--- a/tests/random-test-client.c
+++ b/tests/random-test-client.c
@@ -60,7 +60,9 @@ int main(void)
     modbus_set_debug(ctx, TRUE);
 
     if (modbus_connect(ctx) == -1) {
-        fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+        char buf[128];
+        fprintf(stderr, "Connection failed: %s\n",
+            modbus_strerror_r(errno, buf, sizeof(buf)));
         modbus_free(ctx);
         return -1;
     }
diff --git a/tests/random-test-server.c b/tests/random-test-server.c
index a064fa8a3..09a9c4665 100644
--- a/tests/random-test-server.c
+++ b/tests/random-test-server.c
@@ -18,13 +18,15 @@ int main(void)
     int s = -1;
     modbus_t *ctx;
     modbus_mapping_t *mb_mapping;
+    char errbuf[128];
 
     ctx = modbus_new_tcp("127.0.0.1", 1502);
     /* modbus_set_debug(ctx, TRUE); */
 
     mb_mapping = modbus_mapping_new(500, 500, 500, 500);
     if (mb_mapping == NULL) {
-        fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno));
+        fprintf(stderr, "Failed to allocate the mapping: %s\n",
+            modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
         modbus_free(ctx);
         return -1;
     }
@@ -46,7 +48,8 @@ int main(void)
         }
     }
 
-    printf("Quit the loop: %s\n", modbus_strerror(errno));
+    printf("Quit the loop: %s\n",
+        modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
 
     if (s != -1) {
         close(s);
diff --git a/tests/unit-test-client.c b/tests/unit-test-client.c
index 6a25d3622..5086c2ad5 100644
--- a/tests/unit-test-client.c
+++ b/tests/unit-test-client.c
@@ -138,7 +138,9 @@ int main(int argc, char *argv[])
 
     modbus_get_response_timeout(ctx, &old_response_to_sec, &old_response_to_usec);
     if (modbus_connect(ctx) == -1) {
-        fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+        char buf[128];
+        fprintf(stderr, "Connection failed: %s\n",
+            modbus_strerror_r(errno, buf, sizeof(buf)));
         modbus_free(ctx);
         return -1;
     }
diff --git a/tests/unit-test-server.c b/tests/unit-test-server.c
index 561d64d01..0124b44a3 100644
--- a/tests/unit-test-server.c
+++ b/tests/unit-test-server.c
@@ -43,6 +43,7 @@ int main(int argc, char *argv[])
     uint8_t *query;
     int header_length;
     char *ip_or_device;
+    char errbuf[128];
 
     if (argc > 1) {
         if (strcmp(argv[1], "tcp") == 0) {
@@ -105,7 +106,8 @@ int main(int argc, char *argv[])
                                                   UT_INPUT_REGISTERS_ADDRESS,
                                                   UT_INPUT_REGISTERS_NB);
     if (mb_mapping == NULL) {
-        fprintf(stderr, "Failed to allocate the mapping: %s\n", modbus_strerror(errno));
+        fprintf(stderr, "Failed to allocate the mapping: %s\n",
+            modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
         modbus_free(ctx);
         return -1;
     }
@@ -131,7 +133,8 @@ int main(int argc, char *argv[])
     } else {
         rc = modbus_connect(ctx);
         if (rc == -1) {
-            fprintf(stderr, "Unable to connect %s\n", modbus_strerror(errno));
+            fprintf(stderr, "Unable to connect %s\n",
+                modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
             modbus_free(ctx);
             return -1;
         }
@@ -212,7 +215,8 @@ int main(int argc, char *argv[])
         }
     }
 
-    printf("Quit the loop: %s\n", modbus_strerror(errno));
+    printf("Quit the loop: %s\n",
+        modbus_strerror_r(errno, errbuf, sizeof(errbuf)));
 
     if (use_backend == TCP) {
         if (s != -1) {